The present invention relates to the field of gaskets and more particularly to the field of machines for making gaskets.
Gaskets are used to make pressure tight joints between stationary parts. Gaskets are made of thin deformable material, usually in the form of a ring. Typically, gaskets are made on punch presses. Dies are made, and fastened to the moveable jaw of the press. Then one or more layers of sheet stock are fed between the jaw and the bed of the machine. At each stroke of the press, gaskets are cut. After cutting, useable gaskets must be removed from the waste which consists of the center scrap and other left over material. In the batch process, one or more lengths of material at a time are fed into a press containing cutting dies. Then the gaskets must be separated from the scrap.
Since gasket making is a labor intensive, batch process, people have designed machines which will automatically produce gaskets and similar products. U.S. Pat. No. 2,692,020 discloses a portable die cutting and work feeding apparatus in which multiple layers of cloth with cardboard and a movable belt underneath and cutting dies on top, are laid out on a table. A portable platen press is moved to one end of the table. The assembly of cloth, etc. is moved under the platen and the press activated. Then the cut cloth is moved out from under the platen.
U.S. Pat. No. 3,701,275 discloses a machine for making spacer-expanders for piston oil rings. The machine comprises a punch press having a plurality of stations through which strip stock is fed progressively at accurately predetermined increments. The stations perform such operations as blanking, piercing bending, etc.
U.S. Pat. No. 3,801,406 discloses a method of making gaskets by producing a continuous strip of sheet stock, punching to form blanks, and vulcanizing under pressure.
U.S. Pat. No. 5,019,314 discloses a process for die cutting a sheet of thermoplastic material imprinted with data of limited spacial displacement in which the data is sequentially die cut in alternating rows and lines in a plurality of die cutting stations until all data has been cut with a residual attachment to the sheet.
U.S. Pat. No. 5,346,664 discloses an apparatus for forming a continuous ribbon of connected dish-shaped sequins. The apparatus includes a supply reel, a take-up reel, a punch and die set and a motor system to incrementally move material from the supply reel, through the punch and die set and onto the take-up reel.
U.S. Pat. No. 5,437,828 discloses a method of making photographic film spools involving continuously forming and punching out flanges and assembling them onto spool cores.
The disadvantages of these machines are that punching of the sheet must still be done flat in the equivalent of a punch press, the process must be carried out incrementally and not continuously, and such machines have many moving parts and are expensive to build and maintain. To truly streamline the process of making gaskets, and thus make gaskets more cheaply, a fully continuous process is needed. Development of a machine which can fabricate gaskets and similar parts truly continuously represents a great improvement in the field of machine design and satisfies a long felt need of the gasket maker and user.